Question

我在Rust中编写LoG过滤器，我想使用|作为元素范围乘法运算符（a_{i,j} * b_{i,j}）的运算符，但是编译器抱怨Output结果。它说self[(i, j)] * out[(i, j)]不等于Mul<N>::Output。

impl<N> BitOr<Matrix<N>> for Matrix<N> where N: Mul<N> {
    type Output = Matrix<N>;

    fn bitor(self, other: Matrix<N>) -> Matrix<N> {
        if self.width() != other.width() ||
            self.height() != other.height() {
                panic!("Matrices need to have equal dimensions");
            }

        let mut out = Matrix::new(self.width(), self.height());

        for i in 0..(self.width()) {
            for j in 0..(self.height()) {
                out[(i, j)] = self[(i, j)] * out[(i, j)];
            }
        }

        out
    }
}

有没有办法根据Mul<N>::Output类型设置输出？

Answer 1

我想这应该有效：

impl<N> BitOr<Matrix<N>> for Matrix<N> where N: Mul<N> {
    type Output = Matrix<<N as Mul<N>>::Output>;

    fn bitor(self, other: Matrix<N>) -> Matrix<<N as Mul<N>>::Output> {
        if self.width() != other.width() ||
            self.height() != other.height() {
                panic!("Matrices need to have equal dimensions");
            }

        let mut out = Matrix::new(self.width(), self.height());

        for i in 0..(self.width()) {
            for j in 0..(self.height()) {
                out[(i, j)] = self[(i, j)] * out[(i, j)];
            }
        }

        out
    }
}

Answer 2

你没有提供一个小的可运行的例子，所以我自己做了。这有效：

use std::ops::{Mul,BitOr};

#[derive(Copy,Show)]
struct Matrix<N>(N, N);

impl<N> BitOr<Matrix<N>> for Matrix<N> where N: Mul<N, Output=N> {
    type Output = Matrix<N>;

    fn bitor(self, other: Matrix<N>) -> Matrix<N> {
        Matrix(self.0 * other.0, self.1 * other.1)
    }
}

fn main() {
    let a = Matrix(-1,-1);
    let b = Matrix(2,3);
    let c = a | b;

    println!("{:?}", c)
}

我必须做的主要事情是N: Mul<N, Output=N>，它指定N必须可以与另一个N 相乘，而会导致另一个{{1} }}

参数化结构的运算符依赖于另一个运算符

2 个答案: